Most of us collect something. For some, it's rare coins. For others, it's baseball cards. Still others collect clothes.

Some people collect investments. They may own a dozen funds in their 401(k) plan, another half dozen funds outside of it, and 10 or 15 stocks. In a recent poll of Morningstar.com users, the median number of holdings was 29. That's a lot of investments.

The problem with owning too many funds and stocks is that you can easily lose sight of the forest for the trees. You start out as an investor with an investment goal and a portfolio tailored to you and turn into a collector who has forgotten what your goals are.